1. Field of the Invention
The invention relates to drives for deflectable rolls such as shell type rolls.
2. Description of the Prior Art
Rolls of this type typically include a bendable inner non-rotatable shaft on which a shell roll is mounted for rotation. The inner shaft conventionally is mounted at its ends in pedestals at least one of which also commonly supports a fixed axis gear drive. When a load is applied to the shell roll such as in a calender the inner shaft bends while support means acting between the shaft and the inside of the shell roll maintains the outer surface of the shell roll substantially straight. Such rolls typically are shown in U.S. Pat. No. 2,908,964 to Appenzeller and U.S. Pat. No. 3,587,152 to Hold. During loading of the roll such a support system maintains a uniform nip pressure along the length of the shell roll against a cooperating roll but significant bodily deflection occurs along the fixed shaft. This results in substantial misalignment of the shaft and the shell roll axes. Such misalignment also causes misalignment of the fixed axis gear drive and the deflectable shell roll gearing, which drive must provide substantial power transmission. Typical of loads that must be accommodated may be provided by a rotary power source such as a 300 h.p., 1200 RPM d.c. electric motor.
One solution to the gear misalignment is illustrated in U.S. Pat. No. Re. 27,445 to Kuehn in which the fixed axis portion of the gear drive is supported in a triple race bearing mounted in a fixed pedestal. The deflectable axis part of the gear drive associated with the shell roll is connected to the fixed axis gearing by a flexible gear spline extending therebetween. Another solution is shown in U.S. Pat. No. 3,855,681 to Andriola et al which also involves a flexible gear spline connection to accommodate the gear misalignment. Both of these solutions typically involve relatively complex mechanisms which also accommodate limited misalignment and separation of meshed gear teeth.